But can the nearly broke Philadelphia School District afford to continue to expand the effort, which requires additional funds from the district's coffers?
Penny Nixon, the district's chief academic officer, called the results as highlighted in the Research for Action study "promising" but would not say whether the district would go forward with the Renaissance effort.
Renaissance Schools fall into two categories - schools given by the district to charters to overhaul, and district-run Promise Academies, which operate with extra per-pupil funding. The schools were the signature initiative of former Superintendent Arlene C. Ackerman.
As the district's budget crisis worsened this school year, officials cut spending at Promise Academies and dismantled the central office responsible for running them.
There are 13 Renaissance charters and nine Promise Academies operating this year.
The district, which must close a $38.8 million budget gap by June and faces a shortfall of at least $269 million for next year, has solicited proposals for turnaround teams for a third year of Renaissance Schools.
Officials had said they would announce the turnaround-team finalists this week, but a district spokesman said Tuesday that the timeline has yet to be finalized.
School Reform Commission Chairman Pedro Ramos said last month that the district had not abandoned its commitment to the school turnarounds. He and others have signed on to the "Great Schools Compact," a document that promises to eliminate 50,000 seats in low-performing schools.
Philadelphia has already won $100,000 from the Bill and Melinda Gates Foundation and hopes to win more to do turnaround work.
Mayor Nutter, in a statement, seemed to signal that the Renaissance effort should continue.
"For years in Philadelphia, we've struggled with how to turn around our lowest-performing schools. This study suggests we might be on the right track. Frankly, I'm very excited by this," the mayor said.
Researchers found that more students at the K-8 Renaissance Schools met state standards in math and reading, and fewer fell into the lowest category - "below basic" performance. Attendance at those schools also improved.
There was no significant difference in performance between district-run Promise Academies and charter Renaissance Schools - both produced gains.
And comparisons among individual providers - the School District, Mastery Charter Schools, Universal Cos., ASPIRA, and Young Scholars Academy - showed that all did about equally well in terms of their K-8 gains.
Though some have raised concerns about charter providers pushing out students, the research showed that was not the case.
"We don't see any evidence that the school populations changed," Shaw said.
Researchers found that the overhauled high schools did not have the improvements and attendance boosts seen in elementary schools. Vaux and University City, the two high schools now in their second year as Promise Academies, showed no major changes in attendance and achievement.
But that's not enough to label the high schools a failure, the researchers said.
High schools have traditionally been tougher to turn around, and a lack of first-year gains "is consistent with previous research in school turnaround initiatives at the high school level," researchers wrote.
Shaw, the Research for Action chief, warned against overinterpreting the results and noted that "what's going to be really important is to follow these schools over time to see if the level of improvement is sustained in subsequent years."
The schools were measured on test scores and attendance.
An earlier Research for Action report highlighted progress in school climate but raised some concerns, including the operation of some advisory councils, which are designed to incorporate parent and community voices in school decisions.
Eva Gold, one of the study authors, said those bumps were to be expected in first-year turnarounds.
Gold continued to study two Promise Academies this school year, and said that despite budget cuts and high teacher turnover, "there was a considerable degree of comfort with the 'Promise Way' now," that positive changes in school climate were sustained and principals felt like they would start to see bigger academic gains.
The report is, in a sense, an endorsement of the controversial former superintendent's main academic program. Ackerman left in August in a bitter battle over finances, management style, and leadership capacity.
Reached Tuesday, Ackerman said she was not surprised by the study's results and extended her congratulations to the principals, students, and communities who "believed in this process."
"We already know everything we need to know about how to educate all children well," Ackerman said in an e-mail. "The real question is whether the Philadelphia School District has the political will to do what is right for all children regardless of where they live, who their parents happen to be, or any other life circumstance that may be beyond their control."
The report was commissioned by the Accountability Review Council, a national panel established to evaluate the district's progress.
Research for Action plans a final report on the subject.
Contact staff writer Kristen Graham at 215-854-5146 or email@example.com, or on Twitter @newskag. Read her blog, "Philly School Files," at www.philly.com/schoolfiles.